gitk: Fix bugs in setting rowfinal
gitk: Fix bugs in setting rowfinal

We weren't updating the rowfinal list in insertrow and removerow, so
it was getting out of sync with rowidlist, which resulted in Tcl errors.
This also optimizes the setting of rowfinal in layoutrows a bit.

Signed-off-by: Paul Mackerras <19a0ba370c443ba08d20b5061586430ab449ee8c@samba.org>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git